Going through menopause at a later age increases the risk of breast cancer. For example, studies show that women who go through menopause after age 55 have about a 30 percent higher risk of breast cancer than women who do so before age 45 .
A pooled analysis of data from more than 400,000 women found that for every year older a woman was at menopause, breast cancer risk increased by about three percent .
The increased breast cancer risk linked to an older age at menopause is likely due, at least in part, to the amount of estrogen a woman is exposed to in her life. A higher lifetime exposure to estrogen is related to an increase in breast cancer risk .
The later a woman goes through menopause, the longer her breast tissue is exposed to estrogens released during her menstrual periods and the greater her lifetime exposure to estrogen.
Learn more about estrogen and breast cancer risk.
For a summary of research studies on menopause and breast cancer, visit the Breast Cancer Research Studies section.